Just an FYI, Borderlands 2 is a SteamPlay game. So regardless of what platform you buy it for (Windows or OSX), you get both versions of the game. So this deal (and all future deals on Steamplay games) are good for both gamers running either OSX or Windows.

I posted this on an earlier deal for Borderlands 2, so I'll just C&P it here:

FYI, to get the full Borderlands 2 experience you'll need the following DLCs